1. Field
The present invention relates generally to the field of communications, and more specifically, to communications in a cellular communication system.
2. Background
A cellular communication system may operate in accordance with code division multiple access (CDMA) communication technique. Several CDMA systems have been in commercial operations for a number of years. In CDMA communication systems, a number of users in the same geographical area may choose to operate on a common carrier frequency. The signal from each user is encoded according to a unique assigned code. A receiver decodes each signal according to the assigned code. A receiver may receive signals from different users with a common carrier frequency. While a signal for one user is being decoded, the signals transmitted from all other users may be treated as interference. Excessive transmission by different users may cause interference for other users in addition to causing system overload at a base station. In a CDMA system, the power level of signals transmitted by different users of the system is controlled to control the interference level based on the system capacity. Moreover, for effective utilization of the channel resources in the CDMA communication system, the power level of each transmitted signal is controlled. The power level of each signal is controlled at the transmitter to maintain an adequate quality of reception at a receiving end. Other reasons, such as conserving battery power, for controlling power level of signals in a CDMA system are well known by one of ordinary skill in the relevant art.
Although the power level transmitted from each mobile station is controlled to maximize the use of the available channels, very often, more mobile stations may attempt to access the base station than the number of available channels. In such a case, some mobile stations may be denied access to the base station due to lack of available channels. Rejecting a request for a call has several negative effects. One effect in particular is the amount of processing and bandwidth at the base station allocated to process the rejected call. Another effect is use of the mobile station power to initiate such a call request without a success. Moreover, during call request attempt, the mobile station may gradually increase its transmit power level. The mobile station power level during the call request period may effect communications of other mobile stations.
To this end as well as others, there is a need for an effective control of call request in a communication system.